Material of light emitting layer, manufacturing method thereof, and electroluminescent device

ABSTRACT

A material of a light emitting layer, a manufacturing method thereof, and an electroluminescent device are disclosed. The material of the light emitting layer includes a spiral nanotube structure and luminescent particles. The manufacturing method of the material of the light emitting layer includes steps of manufacturing the spiral nanotube structure and steps of manufacturing a guest-host structure. The manufacturing method is easily achieved, and a compatibility of the material is high.

FIELD OF INVENTION

The present disclosure relates to the field of display technology, andin particular, to a material of a light emitting layer, a manufacturingmethod thereof, and an electroluminescent device.

BACKGROUND OF INVENTION

Currently, organic light-emitting diode (OLED) devices are superior toliquid crystal displays (LCDs) in the display industry and have become amain representative of high-end markets, since the OLED devices haveadvantages of a desired display effect, light weight, and achievablecurved display. However, on the contrary to the display of the OLED,costs and display lifespans of the OLED devices are still aspectsrequired to be continuously improved. In structures of the OLED devices,in addition to light emitting parts, polarizers play a considerablyimportant role in the display effect of the OLED devices. Due to aserious metal reflection in the devices, the OLED devices require toabsorb ambient light with the polarizers to maintain a luminancecontrast of the OLED itself. Like the LCDs, the addition of thepolarizers causes an overall light extraction efficiency to be lost bymore than one-half. If this part could be improved to reduce the loss oflight energy, it will greatly contribute to the display lifespans of theOLED devices.

Therefore, a material of a light emitting layer, a manufacturing methodthereof, and an electroluminescent device are necessary to be providedto overcome the problems existing in the conventional technology.

SUMMARY OF INVENTION Technical Problem

For the above shortcomings and defects existing in the conventionaltechnology, one of purposes in the present disclosure is to provide amaterial of a light emitting layer and a manufacturing method thereof.Emitted light may be modulated to circularly polarized light by usingchiral properties of the material of the light emitting layer. Incomparison to synthesizing a light emitting material which directlyemits the circularly polarized light, the method is easily achieved, anda compatibility of the material is high.

Technical Solutions

Another purpose of the present disclosure is to provide anelectroluminescent device. A light emitting layer of theelectroluminescent device employs the material of the light emittinglayer. A light extraction efficiency may be increased by 40% to 50% bychanging a polarization state of light emitted by the electroluminescentdevice and using a circular polarizer, thereby enhancing the lightextraction efficiency of the device, and improving the light-emittinglifespan of the electroluminescent device as well.

In order to achieve the above-mentioned purposes, the present disclosureprovides a material of the light emitting layer including a spiralnanotube structure and luminescent particles uniformly distributed inthe spiral nanotube structure.

Furthermore, a particle diameter of the spiral nanotube structure rangesfrom 20 nm to 40 nm, and a particle diameter of the luminescentparticles ranges from 1 nm to 100 nm.

Furthermore, material of the spiral nanotube structure is a singlechirality nanotube material.

Furthermore, a chemical structural formula of the spiral nanotubestructure is:

Moreover, material of the luminescent particles includes at least one ofquantum dot luminescent particles, lanthanide nanocrystals, andperovskite nanocrystals.

Moreover, the material of the light emitting layer further includesdimethylformamide.

The present disclosure further provides a manufacturing method of thematerial of the light emitting layer including steps of:

manufacturing a spiral nanotube structure and providing luminescentparticles; and

mixing a quantity of the spiral nanotube structure with a quantity ofthe luminescent particles to obtain a mixture, adding the mixture to adimethylformamide solvent, and heating the mixture and thedimethylformamide solvent in a closed environment until the mixturedissolved in the dimethylformamide solvent, followed by standing andcooling the mixture to a room temperature, so that the luminescentparticles are uniformly distributed in the spiral nanotube structure.

Furthermore, when a particle diameter of the luminescent particlesranges from 20 nm to 40 nm, a proportion of the spiral nanotubestructure to the luminescent particles is (10 to 17):1; and when theparticle diameter of the luminescent particles ranges from 1 nm to 20 nmand/or 40 nm to 100 nm, the proportion of the spiral nanotube structureto the luminescent particles is (5 to 30):1.

Furthermore, the step of manufacturing the spiral nanotube structureinclude:

placing N-tert-butoxycarbonyl-L-glutamic acid, octadecylamine, and acatalyst into a reaction vessel to fully react and obtain a firstreaction solution, and adding tetrahydrofuran into the first reactionsolution to dissolve residual reactants, thus purifying and obtainingintermediate compounds;

placing the intermediate compounds, dichloromethane, and trifluoroaceticacid into a reaction vessel to fully react and obtain a second reactionsolution, using a rotary evaporator to remove excess solvent in thesecond reaction solution, and dissolving residual reactants intetrahydrofuran, followed by adding the residual reactants into sodiumbicarbonate solution, thus obtaining a target compound being a white andsolid substance;

adding the target compound into tetrahydrofuran, and performingrecrystallization purification; and

mixing a quantity of the purified target compound with a quantity ofalcohol solvent to obtain a mixture, heating the mixture to boil in aclosed environment, and cooling the mixture to a room temperature, thusforming the spiral tube structure.

The present disclosure further provides an electroluminescent deviceincluding the above-mentioned material of the light emitting layer.

Furthermore, the electroluminescent device further includes a circularpolarizer disposed on the light emitting layer.

Advantageous Effects

Technical effects of the present disclosure are that the presentdisclosure provides a material of a light emitting layer and amanufacturing method thereof, and the emitted light may be modulated tothe circularly polarized light by using the chiral properties of thematerial of the light emitting layer. In comparison to synthesizing thelight emitting material which directly emits the circularly polarizedlight, the method is easily achieved, and the compatibility of thematerial is high. The present disclosure also provides anelectroluminescent device. The light emitting layer of theelectroluminescent device employs the material of the light emittinglayer. The light extraction efficiency may be increased by 40% to 50% bychanging the polarization state of the light emitted by theelectroluminescent device and using a circular polarizer, therebyenhancing the light extraction efficiency of the device, and improvingthe light-emitting lifespan of the electroluminescent device as well.

DESCRIPTION OF DRAWINGS

FIG. 1 is a structural schematic view of material of a light emittinglayer described in embodiments of the present disclosure.

FIG. 2 is a structural schematic view of an electroluminescent devicedescribed in embodiments of the present disclosure.

FIG. 3 is a structural schematic view of a circular polarizer in FIG. 2.

FIG. 4 is a structural schematic view of a linear polarizer in FIG. 2.

A part of components is marked as follows:

10 material of light emitting layer, 11 spiral nanotube structure, 12luminescent particle, 13 dimethylformamide, 20 electroluminescentdevice, 21 light emitting layer, 22 circular polarizer, 221 λ/4 waveplate, 222 linear polarizer, 31 ambient light, 32 emitted light

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In combination with accompanying drawings in embodiments of the presentdisclosure below, technical solutions in the embodiments of the presentdisclosure are clearly and completely described. Obviously, thedescribed embodiments are merely a part of the embodiments of thepresent disclosure, rather than all the embodiments. Based on theembodiments in the present disclosure, all of other embodiments obtainedby those skilled in the art without making for creative efforts fallwithin the protection scope of the present disclosure.

The term “made by” is synonymous with the term “comprise”. The termsherein “comprise”, “include”, “have”, “contain”, or any other variantsmean “including but not limited to”. For example, a composition, step,method, product, or device containing the listed elements is notnecessary to be limited to those elements, but may include otherelements which are not explicitly listed or elements which are inherentin such a composition, step, method, product, or device.

The terms “first” and “second” are merely used for descriptive purposes,and cannot be understood to indicate or imply the relative importance orimplicitly specify the number of the indicated technical features. Thus,the features defined by “first” and “second” may explicitly orimplicitly include one or more of the features. In the description ofthe present disclosure, the term “a plurality of” means two or more thantwo, unless specifically defined otherwise.

Besides, it should be noted that steps of all methods described hereincan occur out of the order in some alternative implementations. Forexample, two steps shown to be in succession may actually be performedsubstantially simultaneously, or the two steps may sometimes beperformed in the reverse order.

As shown in FIG. 1, the present disclosure provides a material of alight emitting layer 10 including a spiral nanotube structure 11 andluminescent particles 12, which present a guest-host structure. A mainbody of the guest-host structure is the spiral nanotube structure 11,and the luminescent particles 12 are uniformly distributed in the spiralnanotube structure 11, especially in a tubular structure of the spiralnanotube structure 11.

Material of the spiral nanotube structure 11 has chiral properties, sothat the material of the light emitting layer 10 has chiral properties.The chiral properties of the material of the light emitting layer 10 maymodulate emitted light to circularly polarized light. In comparison tosynthesizing a light emitting material which directly emits thecircularly polarized light, the method is easily achieved, and acompatibility of the material is high.

In the embodiments, in the material of the light emitting layer 10, aparticle diameter of the spiral nanotube structure 11 ranges from 20 nmto 40 nm, and a particle diameter of the luminescent particles 12 rangesfrom 1 nm to 100 nm.

In the embodiments, material of the spiral nanotube structure 11 is asingle chirality nanotube material.

In the embodiments, a chemical structural formula of the spiral nanotubestructure 11 is:

In the embodiments, material of the luminescent particles 12 includesquantum dot luminescent particles, lanthanide nanocrystals, orperovskite nanocrystals.

In the embodiments, material of the luminescent particles 12 furtherincludes dimethylformamide 13.

The present disclosure also provides a manufacturing method of thematerial of a light emitting layer 10 including steps of:

S1: manufacturing the spiral nanotube structure 11 and providing theluminescent particles 12; and

S2: mixing a quantity of the spiral nanotube structure 11 with aquantity of the luminescent particles 12 to obtain a mixture, adding themixture to a dimethylformamide solvent, and heating the mixture and thedimethylformamide solvent in a closed environment until the mixturedissolved in the dimethylformamide solvent, followed by standing (about30 min to 60 min) and cooling the mixture to a room temperature, thusforming the guest-host structure in which the luminescent particles 12are uniformly distributed in a tubular space of the spiral nanotubestructure 11.

In the embodiments, the particle diameter of the spiral nanotubestructure 11 ranges from 20 nm to 40 nm, and the particle diameter ofthe luminescent particles 12 ranges from 1 nm to 100 nm.

In the embodiments, when the particle diameter of the luminescentparticles ranges from 20 nm to 40 nm, a proportion of the spiralnanotube structure 11 to the luminescent particles 12 is (10 to 17):1;and when the particle diameter of the luminescent particles 12 rangesfrom 1 nm to 20 nm and/or 40 nm to 100 nm, the proportion of the spiralnanotube structure 11 to the luminescent particles 12 is (5 to 30):1.

In the embodiments, the material of the spiral nanotube structure 11 isa single chirality nanotube material.

In the manufacturing method of the material of the light emitting layer10, the chiral properties of the material of the light emitting layer 10may modulate the emitted light to the circularly polarized light. Incomparison to synthesizing the light emitting material which directlyemits the circularly polarized light, the method is easily achieved, andthe compatibility of the material is high.

In order to illustrate the manufacturing method for manufacturing thespiral nanotube structure 11 of the present disclosure in detail, areaction formula is provided, substantially as shown in formula (1):

The step S1 of manufacturing the spiral nanotube structure 11 of theembodiments is illustrated in detail by combining with the formula (1)below, including the steps as follows:

a step S11 of placing N-tert-butoxycarbonyl-L-glutamic acid,octadecylamine, and a catalyst into a reaction vessel to fully react andobtain a first reaction solution, and adding tetrahydrofuran into thefirst reaction solution to dissolve residual reactants, thus purifyingand obtaining intermediate compounds; wherein theN-tert-butoxycarbonyl-L-glutamic acid is obtained by protecting theglutamic acid with the tert-butoxycarbonyl group in advance; in formula(1), the catalyst includes 1-Hydroxybenzotriazole (HOBt), carbodiimide(EDC), and hydrochloric acid (HCl), the hydrochloric acid is used toremove protecting groups of the intermediate compounds, that is, thetert-butoxycarbonyl group is removed, and a chemical structural formulaof the intermediate compounds is:

a step S12 of placing the intermediate compounds (3.575 g, 4.77 mmol),dichloromethane (CH₂Cl₂)(50 mL), and trifluoroacetic acid (CF₃COOH)(8mL) into a reaction vessel, mixing the intermediate compounds, thedichloromethane, and the trifluoroacetic acid in a room temperature forabout 3 hours to fully react and obtain a second reaction solution,using a rotary evaporator to remove excess solvent in the secondreaction solution, and dissolving residual reactants in tetrahydrofuran(THF), followed by adding the residual reactants into sodium bicarbonatesolution (NaHCO₃), thus obtaining a target compound being a white andsolid substance; wherein in the formula (1), a chemical structuralformula of the target compound is the chemical structural formula of thespiral nanotube structure 11 as follows:

a step S13 of adding the target compound into tetrahydrofuran, andperforming recrystallization purification; and

a step S14 of mixing a quantity of the purified target compound with aquantity of alcohol solvent to obtain a mixture, heating the mixture toboil, i.e., at 75° C., in a closed environment for 3 minutes and coolingthe mixture to a room temperature with a cooling rate of 10° C./min,thus forming the spiral tube structure.

As shown in FIG. 2, the present disclosure also provides anelectroluminescent device 20 including a light emitting layer 21 and acircular polarizer 22 which are stacked with each other. The circularpolarizer 22 is disposed on the light emitting layer 21. Material usedfor the light emitting layer 21 is the above-mentioned material of thelight emitting layer 10.

The manufacturing of the light emitting layer 21 may be performed byusing the inkjet printing or other fixed-point coating methods. Based ondifferent color matching, the material of the film layer is coated on orshaped in a pixel structure with the corresponding color.

As shown in FIG. 2, according to a work principle of theelectroluminescent device 20, after ambient light 31 is reflected, thereflected ambient light 31 is emitted 22 by the circular polarizer 22again. After the ambient light passed the circular polarizer 22 twice,22 light energy is entirely absorbed. A structural change of the lightemitting layer 21 does not affect a blocking effect of the circularpolarizer on the ambient light 31.

The circular polarizer 22 includes a λ/4 wave plate 221 and a linearpolarizer 222. FIG. 3 is a structural schematic view of the λ/4 waveplate 221, and FIG. 4 is a structural schematic view of the linearpolarizer 222. In order to ensure the electroluminescent device 20achieves a highest light extraction efficiency, a polarization state ofthe emitted light 32 of the electroluminescent device 20 requires tocorrespond to arrangement of a polarization axis of the polarizer.Because the ambient light 31 and the emitted light 32 are the circularlypolarized light, the arrangement of the linear polarizer 222 requires toensure that the emitted light in the polarization state entirely passesthe polarizer 222. For example, if an angle between the light axes whichare a light transmission axis of the linear polarizer 222 shown in FIG.4 (represented by a line segment in FIG. 4) and a light transmissionaxis of the λ/4 wave plate 221 shown in FIG. 3 (represented by a linesegment in FIG. 3) is 45 degrees in a counterclockwise direction, theemitted light of the electroluminescent device 20 is configured to beright-handed polarized light, and a chiral direction of the spiralnanotube structure 11 which is selected to compose the light emittinglayer 21 is right-handed. If an angle between the light axes is 135degrees in a counterclockwise direction, the emitted light of theelectroluminescent device 20 is configured to be left-handed polarizedlight, and a chiral direction of the spiral nanotube structure 11 whichis selected to compose the light emitting layer 21 is left-handed.

Technical effects of the present disclosure are that the presentdisclosure provides a material of a light emitting layer 10 and amanufacturing method thereof, and the emitted light may be modulated tothe circularly polarized light by using the chiral properties of thematerial of the light emitting layer 10. In comparison to synthesizingthe light emitting material which directly emits the circularlypolarized light, the method is easily achieved, and the compatibility ofthe material is high. The present disclosure also provides anelectroluminescent device 20. The light emitting layer 21 of theelectroluminescent device employs the material of the light emittinglayer 10. The light extraction efficiency may be increased by 40% to 50%by changing the polarization state of the light emitted by theelectroluminescent device 20 and using the circular polarizer, therebyenhancing the light extraction efficiency of the device, and improvingthe light-emitting lifespan of the electroluminescent device 20 as well.

The above description is only the preferred embodiments of the presentdisclosure. It should be noted that some improvement and modificationscan be made by those skilled in the art without departing from theinventive principles of the present disclosure, and all of theimprovement and modifications are regarded as the protective scope ofthe present disclosure.

1. A material of a light emitting layer, comprising: a spiral nanotubestructure and luminescent particles uniformly distributed in the spiralnanotube structure.
 2. The material of the light emitting layeraccording to claim 1, wherein a particle diameter of the luminescentparticles ranges from 1 nm to 100 nm.
 3. The material of the lightemitting layer according to claim 1, wherein material of the spiralnanotube structure is a single chirality nanotube material.
 4. Thematerial of the light emitting layer according to claim 3, wherein achemical structural formula of the spiral nanotube structure is:


5. The material of the light emitting layer according to claim 1,material of the luminescent particles includes at least one of quantumdot luminescent particles, lanthanide nanocrystals, and perovskitenanocrystals.
 6. A manufacturing method of material of a light emittinglayer, comprising steps of: manufacturing a spiral nanotube structureand providing luminescent particles; and mixing a quantity of the spiralnanotube structure with a quantity of the luminescent particles toobtain a mixture, adding the mixture to a dimethylformamide solvent, andheating the mixture and the dimethylformamide solvent in a closedenvironment until the mixture is dissolved in the dimethylformamidesolvent, followed by standing and cooling the mixture to a roomtemperature, so that the luminescent particles are uniformly distributedin the spiral nanotube structure.
 7. The manufacturing method of thematerial of the light emitting layer according to claim 6, wherein whena particle diameter of the luminescent particles ranges from 20 nm to 40nm, a proportion of the spiral nanotube structure to the luminescentparticles is (10 to 17):1; and when the particle diameter of theluminescent particles is equal to or greater than 1 nm and less than 20nm, and/or is greater than 40 nm and equal to or less than 100 nm, theproportion of the spiral nanotube structure to the luminescent particlesis (5 to 30):1.
 8. The manufacturing method of the material of the lightemitting layer according to claim 6, wherein the step of manufacturingthe spiral nanotube structure includes: placingN-tert-butoxycarbonyl-L-glutamic acid, octadecylamine, and a catalystinto a reaction vessel to fully react and obtain a first reactionsolution, and adding tetrahydrofuran into the first reaction solution todissolve residual reactants, thus purifying and obtaining intermediatecompounds; placing the intermediate compounds, dichloromethane, andtrifluoroacetic acid into a reaction vessel to fully react and obtain asecond reaction solution, using a rotary evaporator to remove excesssolvent in the second reaction solution, and dissolving residualreactants in tetrahydrofuran, followed by adding the residual reactantsinto sodium bicarbonate solution, thus obtaining a target compound beinga white and solid substance; adding the target compound intotetrahydrofuran, and performing recrystallization purification; andmixing a quantity of the purified target compound with a quantity ofalcohol solvent to obtain a mixture, heating the mixture to boil in aclosed environment, and cooling the mixture to a room temperature, thusforming the spiral tube structure.
 9. An electroluminescent device,comprising: a light emitting layer, wherein the light emitting layerincludes the material of the light emitting layer according to claim 1.10. The electroluminescent device according to claim 9, furthercomprising: a circular polarizer disposed on the light emitting layer.